Distributed architecture of touch screen controller SoC for large touch screen panels

Abstract

Currently large touch screen panels (TSP) tend to use projected capacitance technology, which allow multi touch and high sensitivity. For large TSPs with a large number of TX (driving) and RX (sensing) lines, however, it is increasingly challenging to achieve high sensitivity, high detection rate, and multi-touch. In this Paper, we propose a distributed architecture of touch screen controller where multiple controller SoCs collaborate in driving and sensing each section of a large TSP. We show that the proposed architecture and SoC design can increase the detection rate without loss of sensitivity performance. It also allows a smaller SoC implementation, while its chip expandability provides the flexibility of supporting a large range of TSP sizes. We implemented the proposed distributed SoC using TSMC CMOS 0.18um with a low power ARM core, AHB-lite bus, memories, and embedded touch algorithm software.